Grain separator



Sept. 17, 1940. c. c. CALKINS ET AL GRAIN SEPARATOR Filed April 17, 19392 Sheets-Sheet l wefzi afd/x p 7, 1940. c. c. CALKINS El AL 20 GRAINSEPARATOR Filed April 17, 1959 2 Sheets-Sheet 2 Patented Sept. 17, 1940UNlTED STATES hliitfitt GRAIN SEPARATOR Claude G. Calkins and LaurenceA. Hunt,

Spokane, Wash, assignors to Oalkins Manufacturing 00., Spokane,Washington Wash, a corporation of Application April 1'7, 1939, SerialNo. 268,275

Claims.

This invention relates to grain separators of a type disclosed inLetters Patent to Jesse Barber,

No. 2,043,978, dated June 16, 1936, and also in an application filed byus on or about the 15th day 5 of February, 1938, Serial No. 199,608,wherein the threshed grain with its chaff and the finer particles ofstraw are delivered from the thresher beaters onto an endless slatcarrier, beneath which is a shaking screen onto and through which thegrain falls, a blast of air being directed through the screen frombeneath toward the tail end to drive off the fine straw and chaf! thatdrops from the carrier with the grain onto the screen, the cleaned graindropping through the screen and being collected in bags or otherreceptacles by a screw conveyor disposed crosswise beneath the screen.

We have found by extensive experiments that the effectiveness of such aseparator to recover 20 from the tailings of a thresher grain that wouldotherwise be lost depends very largely on the motion given to the screenand to the material on the screen. In the aforesaid Barber patent thescreen frame is horizontally pivoted at its 5 front or receiving end,and its rear or discharge end is supported on a pair of rapidlyrevolving eccentrics so that the screen has an up and down vibratingmovement that is greatest at its rear end and gradually diminishestoward its front pivoted end. In our aforesaid application, Serial No.190,608 the screen frame is horizontally pivoted at its front orreceiving end on theupper ends of a pair of underlying pivoted arms, andis given a compound up and down and fore and 35 aft or undulatingmovement by means of a pair of eccentrics rotating in a pair of bearingblocks attached to the undersides of the side limbs ofv the screenframe.

The main object of our present invention is to provide an improved grainseparator of this general type that will effect an even greatersepararation and recovery of grain from the straw and chaff and acleaner condition of the grain than has heretofore been possible, andthis we accomplish by a novel screen supporting and agitating means bywhich the screen is given a combined upward and rearward swing of suchrapidity and force that the bulk of the fine straw and chaff is tossedupwardly and rearwardly off the top of the screen and is momentarilyfloated on the air blast until the return movement of the screen hasbeen effected and the straw and chaff has resettled on the screen,whereupon the same action of the screen is repeated, so that the linestraw 55 and chaff, indepi ndgntly of the action of the air (01. arc-a2)blast, is gradually shifted step by-step or in successive hops, so tospeak, toward and finally discharged off the tail end of the separator.The momentary floating of the straw and chaff on' the air blast abovethe grain on the screen enables the air to clean the grain much moreeffectively and thoroughly than where the bulk of the straw and chaff isin contact with the top sur face of the screen and mixed with the grainseed during its entire travel over the screen.

An illustrative embodiment of the invention is shown in the accompanyingdrawings, in which- Fig. l is a top plan view of the separator.

Fig. 2 is a longitudinal vertical. section taken on the line 22 of Fig.l, with the blower casing and blower omitted.

Fig 3 is a view similar to Fig. 2, with the frame omitted, and showingthe screen at the limit of its upward and rearward swing. v

Figs. 4, 5 and 6 are diagrams illustrating variations in the steepnessof the swinging movements of the screen obtainable by changing thepoints of suspension of the suspending arms of the screen. I

Fig. '7 is a perspective View, broken off at one corner, of the screen,screen frame, and screen swinging means.

Figs. 8, 9 and 10 are crosssections taken on the correspondinglynumbered lines of 2.

In the assembly views, Figs. 1 and 2, we have shown a portion of theusual housing ii of the threshing portion of the harvester-thresher orcombine, with the foot board or bridge I? extending transversely of thehousing for delivering material to the separator. At the front low" orportion of the housing a conventional fan blower is, indicated by dottedlines in Fig. 1, is located and serves to direct the air blast throughthe throat l4 toward the front end of the separator for the separationof the lighter chaff from the grain.

A separator frame comprises principally side walls I5 and a bottom wallIt, a portion of which latter inclines downwardly toward the front orreceiving end of the separator and merges with a conveyor trough llcontaining a screw conveyor I8 for delivering the salvaged grain at oneside of the machine. On the upper edges of the side Walls are inwardlyextending flanges l9 (Fig. 8) which overhang and protect certain linkbearings later described from the straw and chaff flowing onto theseparator.

Describing now the moving parts of the separator which are housed in theseparator frame, designates as an entirety an. endless conveyor rakecomprising parallel sprocket chains- 2| and cross rods or slats 22, thechains 2i being guided around and supported by sprockets 23, 24 and 25fast on shafts 26, 27 and 28 respectively, journaled in and between theside walls l5 of the housing. Underlying the top lap of the endlessconveyor rake 20 is a screen designated as an entirety by 29. Thestructural details of this screen are best shown in Fig. '7, wherein itwill be seen that the screen frame comprises parallel side bars 30, endbars 3!, and (preferably) an intermediate longitudinal bar 32. Overlyingthe top of the screen frame is a reticulated screen 33 of sufiicientlywide mesh to readily pass the largest size grains that are handled bythe thresher. On the upper sides of the side bars 36 are attached metalstrips 34 to protect the side bars 39 from the wear of the conveyorchains 2i, as shown in Fig. 9; and the outer and bottom sides of theside bars 30 are preferably reinforced by angle bars 35, as shown inFig. 9. At the four corners of the screen frame, the side and endmembers are securely bonded by rectangular strips 36, the horizontallimbs of which are alined with the wear strips 34, and attached to theside rails 35, and the vertical limbs of which are engaged by bolts 31extending through bolt supports 38 welded to the lower horizontal limbof the angle bars 35.

Secured to the cross bar M at the delivery end of the screen frame is anangle bar 39 carrying a rod 40 on which are mounted a series of springtines 4| that form in effect a longitudinal extension of the screen, andthe free upturned ends of the tines overlie a cross bar 42 that is rigidwith a fixed rounded guide 43 that overhangs the sprocket shaft 28 toguide the straw off the end of the separator without clogging the shaftbearings. These last described structural features are disclosed andclaimed in our pending application, Serial No. 190,608, above referredto.

Turning now to those features of the screen support and screen swingingmeans wherein this invention mainly resides, on the side walls I5 at thereceiving end of the separator are mounted a pair of metal straps 44each having a central inwardly offset portion 35 (Fig. 8) containing arow of spaced holes 46, M and 48, the relative disposition of whichholes is best shown in the diagrammatic views, Figs. 4, 5 and 6. Asimilar pair of straps M is mounted on the rear end portions of the sidewalls l5. Suspended from these straps by pivot pins 69 (Fig. 8) whichare adapted to engage with any of the holes 46, 4'! and 48, aredepending links 59 each carrying at its lower end a pin 5| engaged witha bearing block 52 attached to the angle bar 35. As shown in Figs. 2 and3, the links at both ends of the screen are parallel to each other inall positions of the screen; and, to effect the motion of the screen bywhich the chair and fine straw on the screen is repeatedly tossedupwardly and rearwardly by the reciprocations of the screen, the linksare, in all positions of the screen inclined downwardly toward the rearor delivery end of the separator. The practical result of this is bestillustrated in the diagrammatic views, Figs. 4, 5 and 6, from which itwill be seen that the upward path of movement of the screen is along thearcuate lines a, b and c. If the links are pivoted in the holes 58 (Fig.6) the arcuate path a is of minimum height and steepness. If the linksare pivoted in the holes 46 (Fig. 5) the arcuate path 0 is of maximumheight and steepness A h link r pi oted n the holes i! (Fig. 4) thearcuate path I) is of intermediate height and steepness. This manner ofoptionally mounting the links so as to give the screen an upward swingthrough paths of greater or less height and steepness is to accommodatethe separator to the most advantageous handling of different grains,wherein the straw and chaff may be of different specific gravities.

The screen may be swung endwise by any suitable mechanism, but we haveherein illustrated one simple practical mechanism for this purpose.Journaled in and extending between the side walls 85 beneath andcrosswise of the screen is a rotary shaft 53, fast on which are a pairof eccentrics 54. 55 designates each of a pair of transversely flexiblearms, each conveniently made of a steel strip bent and folded on itself.One end of each arm 55 is attached at 56 to the underside of a side railof the screen frame; and in the loop formed by the two limbs of the armat its other end is an eccentric bearing block 5'! with which theeccentric 54 is engaged.

On one end of the shaft 28 is a sprocket 58 (Fig. 1) driven from anysuitable source of power; and on the other end of shaft 28 is a sprocket59 which, through a chain 66, drives a sprocket 6! fast on the shaft 53.

In the operation of the separator, practically all of the clean grainseed is collected in the trough ll at the forward or front end of theseparator. We have also shown herein a second grain trough 62 served bya screw conveyor 63 that is located in the bottom wall l6 of the separator frame rearwardly of the main grain discharge conveyor IB, andthis auxiliary conveyor takes care of and handles a relatively smallquantity of grain and other seed that requires further separating stepsfor the final recovery of the grainseed, or may be used as chicken orstock feed. As the conveyor rake 20 drags the straw over the dischargeend portion of the separator a considerable part of this mixed seeddrops between the tines 4i and is deflected downwardly by an apron 54,from which it passes down the bottom wall I6 into the trough of theauxiliary conveyor 63. This auxiliary separator is disclosed and claimedin our copending application above noted, and forms no part of thepresent invention.

From the foregoing it will be seen that the screen, being suspended ontwo parallel pairs of links has a movement on the principle of aparallel ruler; and further that this movement in the rearward directionis an upward movement throughout, and in the reverse or return directionis a downward movement throughout. Hence, as

before stated, the fine straw and chaff on the screen is successivelytossed upwardly and toward the discharge end of the separator, virtuallyfloating on the upwardly and rearwardly directed current of air duringthe return movement of the screen, if the air blast is on. But even ifthe air blast should fail, the step-by-step advance of the straw andchaff over the screen will occur, because the return arcuate movement ofthe screen is faster than the vertical gravity descent of the straw andchaff onto the screen. This peculiar movement of the screen we havefound to be very effective in separating the grain from the fine strawand chaff with which it is mingled, yielding a larger percentage ofclean grain than is obtainable with the separators of the Barber Patent,above ide 5rd and our aforesaid pendi g application.

Changes in the details of structure and arrangement may be resorted towithin the scope and coverage of the claims.

We claim: 7

1. In a grain separator of the class described, the combination of aframe including side walls, an endless conveyor rack mounted on saidframe, a screen frame and screen underlying the top lap of said conveyorrack, suspending means for said screen comprising a pair of rigid linkspivoted at their upper ends to said side walls and at their lower endsto the sides of said screen frame at each end portion of said screen,said links being inclined downwardly toward the tail end of theseparator in all positions assumed by the screen during its swingingmovement, means for imparting an endwise swinging movement to saidscreen, and means for directing a blast of air through said screen frombeneath.

2. An embodiment of the subject-matter defined in claim 1, wherein meansare provided for pivoting the upper ends of the links at any of aplurality of laterally spaced positions by which to vary the height andsteepness of the upward swing of the screen.

3. An embodiment of the subject-matter .defined in claim 1, wherein aplurality of laterally spaced pivot holes are provided on the side wallsof the separator frame for optional pivoting of the upper ends of thelinks, said holes being so located as to cause said links toeffect-variations in the height and steepness of the upward swing of thescreen.

4. In a grain separator of the class described, the combination of aframe including side walls, an endless conveyor rake mounted in saidframe,

a screen frame and screen underlying the top lap of said conveyor rake,supporting means for said screen comprising a pair of links pivoted atone end on said side walls and at their other ends to said screen frameat each end portion of said screen, means for imparting an endwiseswinging movement to said screen comprising a rotary shaft journaled inand between the side Walls of the separator frame, a transverselyflexible arm attached at one end to the screen, and means on said shaftengaged with the other end of said arm for effecting reciprocatingmovements of said arm, and means for directing a blast of air throughsaid screen from beneath.

5. In a grain separator of the class described, the combination of aframe including side walls, an endless conveyor rack mounted on saidframe, a screen frame and screen underlying the top lap of said conveyorrack, suspending means for said screen comprising a pair of rigid linkspivoted at their upper ends to said side walls and at their lower endsto the sides of said screen frame at each end portion of said screen,and means for imparting an endwise swinging movement to said screencomprising a rotary shaft journaled in.

